Electric shaver

Details Electric shaver Electric shaver

1998-06-16

2001-03-13

Watts, Douglas D. (Department: 3724)

Cutlery

Razors

With cooperating shearing blades

C030S346510

Reexamination Certificate

active

06199282

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotary type electric shaver.
2. Prior Art
A conventional rotary type electric shaver will be described first.
As shown in FIGS.
10
and I
1
, an electric shaver is equipped with at least one shaving unit
54
that consists of a circular outer cutter unit
50
and a circular inner cutter unit
52
which is rotated relative to the outer cutter unit
50
.
The outer cutter unit
50
is provided with two annular blade formation regions
56
a
and
56
b
, and a plurality of hair-entry slits
62
a
and
62
b
of the same width are formed so as to be side by side in the circumferential direction and extend in substantially radial configuration, thus forming slit-form blades
58
a
and
58
b
in the annular blade formation regions
56
a
and
56
b
. For the outer slit-form blades
58
a
, the side walls of the ribs
64
a
which are formed by two adjacent slits
62
a
of the outer blade formation region
56
a
act as blade surfaces for cutting whiskers; and likewise, for the inner slit-form blades
58
b
, the side walls of the ribs
64
b
which are formed by two adjacent slits
62
b
of the inner blade formation region
56
b
act as blade surfaces for cutting the whiskers.
Here, the term “substantially radial configuration” described above refers to the fact that the respective slits
62
a
and
62
b
are formed in a straight line so that the slits extend from the inner circumferences of the respective blade formation regions
56
a
and
56
b
to the outer circumferences of the blade formation regions with the slits inclined at a prescribed angle with respect to the radial direction extending from the center of each of the outer cutter units
50
. In addition, the “prescribed angle” refers to an angle in the range of 0 degrees to 90 degrees (e. g., about 10 degrees). The same is true below. The respective slits
62
a
and
62
b
are formed in the respective blade formation regions
56
a
and
56
b
at equal angular (angle &agr;) intervals.
Furthermore, the inner cutter unit
50
is provided with inner blade bodies
60
which are disposed circumferentially. The tip ends of the respective inner blade bodies
60
are bifurcated as shown in
FIG. 11
, thus forming inner blade elements
60
a
and
60
b
which respectively contact the internal surfaces of the slit-form blades
58
a
and
58
b
. These inner blade elements
60
a
and
60
b
are arranged in concentric annular configurations so as to correspond to the annular blade formation regions
56
a
and
56
b
of the outer cutter unit
50
.
With the structure described above, the slit-form blade
58
a
and inner blade elements
60
a
form an annular cutting blade assembly located around the outer circumference of the shaving unit
54
, and the slit-form blade
58
b
and inner blade elements
60
b
form another cutting blade assembly located around the inner circumference of the shaving unit
54
.
As shown in
FIG. 11
, in the prior art shaver, not only the thickness a and b of the respective slit-form blades
58
a
and
58
b
of the respective blade formation regions
56
a
and
56
b
of the outer cutter unit
50
are formed to be the same (a=b), but also the interior surfaces of the slit-form blades
58
a
and
58
b
arc positioned on the same plane X.
Because of this configuration of the outer cutter unit
50
, the tip ends of the respective inner blade elements
60
a
and
60
b
of the inner cutter unit
52
, which rotate while contacting the interior surfaces of the slit-form blades
58
a
and
58
b
, are also formed so as to be positioned on the same plane X.
However, the above-described conventional electric shaver has problems.
The slits
62
a
and
62
b
of the respective slit-form blades
58
a
and
58
b
of the outer cutter unit
50
extend from the inner circumferences to the outer circumferences of the respective blade formation regions
56
a
and
56
b
in a substantially radial configuration. Furthermore, the respective widths of the inner and outer blade formation regions
56
a
and
56
b
must be a certain predetermined size or greater in order to obtain a maximum possible effective shaving area created by the corresponding inner blade elements
60
a
and
60
b
. Accordingly, the slits
62
a
and
62
b
are generally greater in length than the holes formed in a foil blade of reciprocating type electric shavers. Moreover, the widths d of the slits
62
a
and
62
b
must also have a prescribed size or greater in order to effectively introduce whiskers thereinto.
Consequently, the respective slits
62
a
and
62
b
are inevitably formed large, and this results in that the skin tends to enter into these slits during shaving. Accordingly, it is necessary to form the slit-form blades
58
a
and
58
b
with a certain thickness so that the skin entering the slits
62
a
and
62
b
does not reach the inner cutter unit
52
and cause cutting injuries. Generally, shaving is done by holding the electric shaver in one hand and pressing it against the surface of the skin, moving the shaving unit
54
around on the skin; accordingly, the skin in contact with the area of the side-surface opening on the outer circumferential side of the slit-form blade
58
a
of the blade formation region
56
a
located at the outermost circumference of the outer cutter unit
50
, tends to wrinkle up and easily enters the slits as indicated by arrows A. Accordingly, the thickness a of the slit-form blades
58
a
of the outermost blade formation region
56
a
must have a certain predetermined thickness in order to insure the safety of the user; and as a result, the thickness b of the slit-form blades
58
b
of the inner blade formation region
56
b
correspondingly has a certain thickness so as to conform with the thickness a.
Thus, the deep shaving of whiskers such as that performed by foil blades employed in reciprocating type electric shavers is difficult to accomplish.
SUMMARY OF THE INVENTION
Accordingly, the present invention is to solve the problems described above, and the object of the present invention is to provide an electric shaver which allows deep shaving of whiskers without damaging the skin of the user even with the use of an outer cutter unit that has a slit-form blade.
The above described object of the present invention is accomplished by a unique structure for an electric shaver which includes outer cutter units each of which is provided with a blade formation region of an annular shape with slit-form blades formed therein and inner cutter units each comprising a plurality of inner blade elements arranged in an annular configuration with tip ends contacting the interior surface of the slit-form blades of the outer cutter units while being rotated relative to the outer cutter units; and the electric shaver is characterized in that a plurality of the blade formation regions are formed in the shape of concentric circles in each of the outer cutter units, and the slit-form blades of the blade formation regions other than the outermost blade formation region are formed thinner than those of the outermost blade formation region.
In the structure described above, the slit-form blades in the outermost blade formation region of the outer cutter unit, where the entry of the skin is most likely, are thicker than that of other blade formation region(s), and therefore, the safety of the user is insured when the outer cutter units are moved while being pressed against the skin during shaving; and at the same time, since the slit-form blades of the blade formation region(s) other than the outermost blade formation region is thinner than those of the outermost blade formation region, the deep shaving of whiskers can be accomplished.
Furthermore, when the slits, which comprise the slit-form blades, in the blade formation region(s) other than the outermost blade formation region are formed in smaller number than in the outermost blade formation region, each one of the ribs, which are formed by two adjacent slits, in the blade formation region(s) other than the

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